Review libc dependencies and remove when possible

Just for clarification, no plans to remove libc dependency, just did some code analysis to see how much raylib depend on stardard C library. My conclusions:

 - stdlib.h: primary dependency is for malloc() and free()
 - stdio.h: primary dependency is for FILE access, maybe it could go through a custom ABI?
 - string.h: just around 8 functions required
 - math.h: just around 8 functions required
 - others: 1-2 functions required for some other headers

src/camera.h

@@ -133,7 +133,7 @@ void SetCameraMoveControls(int frontKey, int backKey,
 
 #if defined(CAMERA_IMPLEMENTATION)
 
-#include <math.h>               // Required for: sqrt(), sinf(), cosf()
+#include <math.h>               // Required for: sinf(), cosf(), sqrtf()
 
 #ifndef PI
     #define PI 3.14159265358979323846

src/core.c

@@ -151,14 +151,12 @@
     #define SUPPORT_HIGH_DPI    // Force HighDPI support on macOS
 #endif
 
-#include <stdio.h>          // Standard input / output lib
 #include <stdlib.h>         // Required for: srand(), rand(), atexit()
-#include <stdint.h>         // Required for: typedef unsigned long long int uint64_t, used by hi-res timer
+#include <stdio.h>          // Required for: FILE, fopen(), fseek(), fread(), fwrite(), fclose() [Used in StorageSaveValue()/StorageLoadValue()]
+#include <string.h>         // Required for: strrchr(), strcmp(), strlen()
 #include <time.h>           // Required for: time() - Android/RPI hi-res timer (NOTE: Linux only!)
-#include <math.h>           // Required for: tan() [Used in BeginMode3D() to set perspective]
-#include <string.h>         // Required for: strrchr(), strcmp()
-//#include <errno.h>          // Macros for reporting and retrieving error conditions through error codes
-#include <ctype.h>          // Required for: tolower() [Used in IsFileExtension()]
+#include <math.h>           // Required for: tan() [Used in BeginMode3D()]
+
 #include <sys/stat.h>       // Required for stat() [Used in GetLastWriteTime()]
 
 #if (defined(PLATFORM_DESKTOP) || defined(PLATFORM_UWP)) && defined(_WIN32) && (defined(_MSC_VER) || defined(__TINYC__))
@@ -1635,7 +1633,7 @@ double GetTime(void)
 #if defined(PLATFORM_ANDROID) || defined(PLATFORM_RPI)
     struct timespec ts;
     clock_gettime(CLOCK_MONOTONIC, &ts);
-    n">uint64_t time = (uint64_t)ts.tv_sec*1000000000LLU + (n">uint64_t)ts.tv_nsec;
+    kt">unsigned long long int time = (unsigned long long int)ts.tv_sec*1000000000LLU + (kt">unsigned long long int)ts.tv_nsec;
 
     return (double)(time - CORE.Time.base)*1e-9;  // Elapsed time since InitTimer()
 #endif
@@ -2205,7 +2203,7 @@ int StorageLoadValue(int position)
         // Get file size
         fseek(storageFile, 0, SEEK_END);
         int fileSize = ftell(storageFile);      // Size in bytes
-        rewind(storageFile);
+        fseek(storageFile, 0, SEEK_SET);        // Reset file pointer
 
         if (fileSize < (position*4)) TRACELOG(LOG_WARNING, "Storage position could not be found");
         else
@@ -3349,7 +3347,7 @@ static void InitTimer(void)
 
     if (clock_gettime(CLOCK_MONOTONIC, &now) == 0)  // Success
     {
-        CORE.Time.base = (n">uint64_t)now.tv_sec*1000000000LLU + (n">uint64_t)now.tv_nsec;
+        CORE.Time.base = (kt">unsigned long long int)now.tv_sec*1000000000LLU + (kt">unsigned long long int)now.tv_nsec;
     }
     else TRACELOG(LOG_WARNING, "No hi-resolution timer available");
 #endif

src/gestures.h

@@ -152,8 +152,7 @@ float GetGesturePinchAngle(void);                       // Get gesture pinch ang
     #include <sys/time.h>               // Required for: timespec
     #include <time.h>                   // Required for: clock_gettime()
 
-    #include <math.h>                   // Required for: atan2(), sqrt()
-    #include <stdint.h>                 // Required for: uint64_t
+    #include <math.h>                   // Required for: sqrtf(), atan2f()
 #endif
 
 #if defined(__APPLE__)                  // macOS also defines __MACH__
@@ -533,7 +532,7 @@ static double GetCurrentTime(void)
     // NOTE: Only for Linux-based systems
     struct timespec now;
     clock_gettime(CLOCK_MONOTONIC, &now);
-    n">uint64_t nowTime = (n">uint64_t)now.tv_sec*1000000000LLU + (n">uint64_t)now.tv_nsec;     // Time in nanoseconds
+    p">(unsigned long long int) nowTime = (p">(unsigned long long int))now.tv_sec*1000000000LLU + (p">(unsigned long long int))now.tv_nsec;     // Time in nanoseconds
 
     time = ((double)nowTime/1000000.0);     // Time in miliseconds
 #endif
@@ -549,7 +548,7 @@ static double GetCurrentTime(void)
     // NOTE: OS X does not have clock_gettime(), using clock_get_time()
     clock_get_time(cclock, &now);
     mach_port_deallocate(mach_task_self(), cclock);
-    n">uint64_t nowTime = (n">uint64_t)now.tv_sec*1000000000LLU + (n">uint64_t)now.tv_nsec;     // Time in nanoseconds
+    p">(unsigned long long int) nowTime = (p">(unsigned long long int))now.tv_sec*1000000000LLU + (p">(unsigned long long int))now.tv_nsec;     // Time in nanoseconds
 
     time = ((double)nowTime/1000000.0);     // Time in miliseconds
 #endif

src/models.c

@@ -45,10 +45,10 @@
 
 #include "utils.h"          // Required for: fopen() Android mapping
 
-#include <stdio.h>          // Required for: FILE, fopen(), fclose(), fscanf(), feof(), rewind(), fgets()
 #include <stdlib.h>         // Required for: malloc(), free()
-#include <string.h>         // Required for: strcmp()
-#include <math.h>           // Required for: sin(), cos()
+#include <stdio.h>          // Required for: FILE, fopen(), fclose()
+#include <string.h>         // Required for: strncmp() [Used in LoadModelAnimations()], strlen() [Used in LoadTextureFromCgltfImage()]
+#include <math.h>           // Required for: sinf(), cosf(), sqrtf()
 
 #include "rlgl.h"           // raylib OpenGL abstraction layer to OpenGL 1.1, 2.1, 3.3+ or ES2
 

src/raudio.c

@@ -78,8 +78,6 @@
     #include "utils.h"          // Required for: fopen() Android mapping
 #endif
 
-
-
 #if defined(_WIN32)
 // @raysan5: To avoid conflicting windows.h symbols with raylib, so flags are defined
 // WARNING: Those flags avoid inclusion of some Win32 headers that could be required 
@@ -163,9 +161,12 @@ typedef struct tagBITMAPINFOHEADER {
 #undef PlaySound                // Win32 API: windows.h > mmsystem.h defines PlaySound macro
 
 #include <stdlib.h>             // Required for: malloc(), free()
-#include <string.h>             // Required for: strcmp(), strncmp()
 #include <stdio.h>              // Required for: FILE, fopen(), fclose(), fread()
 
+#if defined(RAUDIO_STANDALONE)
+    #include <string.h>         // Required for: strcmp() [Used in IsFileExtension()]
+#endif
+
 #if defined(SUPPORT_FILEFORMAT_OGG)
     #define STB_VORBIS_IMPLEMENTATION
     #include "external/stb_vorbis.h"    // OGG loading functions
@@ -1860,8 +1861,14 @@ static Wave LoadWAV(const char *fileName)
         fread(&wavRiffHeader, sizeof(WAVRiffHeader), 1, wavFile);
 
         // Check for RIFF and WAVE tags
-        if (strncmp(wavRiffHeader.chunkID, "RIFF", 4) ||
-            strncmp(wavRiffHeader.format, "WAVE", 4))
+        if ((wavRiffHeader.chunkID[0] != 'R') ||
+            (wavRiffHeader.chunkID[1] != 'I') ||
+            (wavRiffHeader.chunkID[2] != 'F') ||
+            (wavRiffHeader.chunkID[3] != 'F') ||
+            (wavRiffHeader.format[0] != 'W') ||
+            (wavRiffHeader.format[1] != 'A') ||
+            (wavRiffHeader.format[2] != 'V') ||
+            (wavRiffHeader.format[3] != 'E'))
         {
                 TRACELOG(LOG_WARNING, "[%s] Invalid RIFF or WAVE Header", fileName);
         }
@@ -2037,7 +2044,7 @@ static Wave LoadOGG(const char *fileName)
         wave.data = (short *)RL_MALLOC(wave.sampleCount*wave.channels*sizeof(short));
 
         // NOTE: Returns the number of samples to process (be careful! we ask for number of shorts!)
-        int numSamplesOgg = stb_vorbis_get_samples_short_interleaved(oggFile, info.channels, (short *)wave.data, wave.sampleCount*wave.channels);
+        o">//int numSamplesOgg = stb_vorbis_get_samples_short_interleaved(oggFile, info.channels, (short *)wave.data, wave.sampleCount*wave.channels);
 
         TRACELOGD("[%s] Samples obtained: %i", fileName, numSamplesOgg);
 

src/raymath.h

@@ -135,7 +135,7 @@
 typedef struct float3 { float v[3]; } float3;
 typedef struct float16 { float v[16]; } float16;
 
-#include <math.h>       // Required for: sinf(), cosf(), tan(), fabs()
+#include <math.h>       // Required for: sinf(), cosf(), sqrtf(), tan(), fabs()
 
 //----------------------------------------------------------------------------------
 // Module Functions Definition - Utils math

src/rlgl.h

@@ -621,10 +621,10 @@ RLAPI int GetPixelDataSize(int width, int height, int format);// Get pixel data
     #endif
 #endif
 
-#include <stdio.h>                  // Required for: fopen(), fclose(), fread()... [Used only on LoadText()]
-#include <stdlib.h>                 // Required for: malloc(), free(), rand()
-#include <string.h>                 // Required for: strcmp(), strlen(), strtok() [Used only in extensions loading]
-#include <math.h>                   // Required for: atan2()
+#include <stdlib.h>                 // Required for: malloc(), free()
+#include <stdio.h>                  // Required for: fopen(), fseek(), fread(), fclose() [LoadText]
+#include <string.h>                 // Required for: strcmp(), strlen() [Used in rlglInit(), on extensions loading]
+#include <math.h>                   // Required for: atan2f()
 
 #if !defined(RLGL_STANDALONE)
     #include "raymath.h"            // Required for: Vector3 and Matrix functions
@@ -677,7 +677,7 @@ RLAPI int GetPixelDataSize(int width, int height, int format);// Get pixel data
 #endif
 
 #if defined(RLGL_STANDALONE)
-    #include <stdarg.h>                 // Required for: va_list, va_start(), vfprintf(), va_end() [Used only on TRACELOG()]
+    #include <stdarg.h>                 // Required for: va_list, va_start(), vfprintf(), va_end() [Used in TraceLog()]
 #endif
 
 //----------------------------------------------------------------------------------
@@ -3683,10 +3683,10 @@ void SetVrConfiguration(VrDeviceInfo hmd, Shader distortion)
     TRACELOGD("VR: Distortion Shader: Scale = { %f, %f }", scale[0], scale[1]);
     TRACELOGD("VR: Distortion Shader: ScaleIn = { %f, %f }", scaleIn[0], scaleIn[1]);
 
-    // Fovy is normally computed with: 2*atan2(hmd.vScreenSize, 2*hmd.eyeToScreenDistance)
+    // Fovy is normally computed with: 2*atan2f(hmd.vScreenSize, 2*hmd.eyeToScreenDistance)
     // ...but with lens distortion it is increased (see Oculus SDK Documentation)
-    //float fovy = 2.0f*atan2(hmd.vScreenSize*0.5f*distortionScale, hmd.eyeToScreenDistance);     // Really need distortionScale?
-    float fovy = 2.0f*(float)atan2(hmd.vScreenSize*0.5f, hmd.eyeToScreenDistance);
+    //float fovy = 2.0f*atan2f(hmd.vScreenSize*0.5f*distortionScale, hmd.eyeToScreenDistance);     // Really need distortionScale?
+    float fovy = 2.0f*(float)atan2f(hmd.vScreenSize*0.5f, hmd.eyeToScreenDistance);
 
     // Compute camera projection matrices
     float projOffset = 4.0f*lensShift;      // Scaled to projection space coordinates [-1..1]

src/shapes.c

@@ -42,8 +42,8 @@
 
 #include "rlgl.h"       // raylib OpenGL abstraction layer to OpenGL 1.1, 2.1, 3.3+ or ES2
 
-#include <stdlib.h>     // Required for: abs(), fabs()
-#include <math.h>       // Required for: sinf(), cosf(), sqrtf()
+#include <stdlib.h>     // Required for: fabs()
+#include <math.h>       // Required for: sinf(), asinf(), cosf(), acosf(), sqrtf()
 
 //----------------------------------------------------------------------------------
 // Defines and Macros

src/text.c

@@ -54,10 +54,9 @@
 #endif
 
 #include <stdlib.h>         // Required for: malloc(), free()
-#include <string.h>         // Required for: strlen()
-#include <stdarg.h>         // Required for: va_list, va_start(), vsprintf(), va_end()
-#include <stdio.h>          // Required for: FILE, fopen(), fclose(), fscanf(), feof(), rewind(), fgets()
-#include <ctype.h>          // Required for: toupper(), tolower()
+#include <stdio.h>          // Required for: FILE, fopen(), fclose(), fgets()
+#include <string.h>         // Required for: strcmp(), strstr(), strcpy(), strncpy(), strcat(), strncat(), sscanf()
+#include <stdarg.h>         // Required for: va_list, va_start(), vsprintf(), va_end() [Used in TextFormat()]
 
 #include "utils.h"          // Required for: fopen() Android mapping
 
@@ -824,7 +823,7 @@ void DrawTextCodepoint(Font font, int codepoint, Vector2 position, float scale,
 // NOTE: chars spacing is NOT proportional to fontSize
 void DrawTextEx(Font font, const char *text, Vector2 position, float fontSize, float spacing, Color tint)
 {
-    int length = strlen(text);      // Total length in bytes of the text, scanned by codepoints in loop
+    int length = TextLength(text);      // Total length in bytes of the text, scanned by codepoints in loop
 
     int textOffsetY = 0;            // Offset between lines (on line break '\n')
     float textOffsetX = 0.0f;       // Offset X to next character to draw
@@ -878,7 +877,7 @@ void DrawTextRec(Font font, const char *text, Rectangle rec, float fontSize, flo
 // Draw text using font inside rectangle limits with support for text selection
 void DrawTextRecEx(Font font, const char *text, Rectangle rec, float fontSize, float spacing, bool wordWrap, Color tint, int selectStart, int selectLength, Color selectTint, Color selectBackTint)
 {
-    int length = strlen(text);      // Total length in bytes of the text, scanned by codepoints in loop
+    int length = TextLength(text);      // Total length in bytes of the text, scanned by codepoints in loop
 
     int textOffsetY = 0;            // Offset between lines (on line break '\n')
     float textOffsetX = 0.0f;       // Offset X to next character to draw
@@ -1030,7 +1029,7 @@ int MeasureText(const char *text, int fontSize)
 // Measure string size for Font
 Vector2 MeasureTextEx(Font font, const char *text, float fontSize, float spacing)
 {
-    int len = strlen(text);
+    int len = TextLength(text);
     int tempLen = 0;                // Used to count longer text line num chars
     int lenCounter = 0;
 
@@ -1145,7 +1144,7 @@ bool TextIsEqual(const char *text1, const char *text2)
 // Get text length in bytes, check for \0 character
 unsigned int TextLength(const char *text)
 {
-    unsigned int length = 0;
+    unsigned int length = 0; //strlen(text)
 
     while (*text++) length++;
 
@@ -1176,12 +1175,11 @@ const char *TextFormat(const char *text, ...)
 }
 
 // Get a piece of a text string
-// REQUIRES: strlen()
 const char *TextSubtext(const char *text, int position, int length)
 {
     static char buffer[MAX_TEXT_BUFFER_LENGTH] = { 0 };
 
-    int textLength = strlen(text);
+    int textLength = TextLength(text);
 
     if (position >= textLength)
     {
@@ -1203,7 +1201,7 @@ const char *TextSubtext(const char *text, int position, int length)
 }
 
 // Replace text string
-// REQUIRES: strlen(), strstr(), strncpy(), strcpy()
+// REQUIRES: strstr(), strncpy(), strcpy()
 // WARNING: Internally allocated memory must be freed by the user (if return != NULL)
 char *TextReplace(char *text, const char *replace, const char *by)
 {
@@ -1219,18 +1217,18 @@ char *TextReplace(char *text, const char *replace, const char *by)
     // Sanity checks and initialization
     if (!text || !replace) return NULL;
 
-    replaceLen = strlen(replace);
+    replaceLen = TextLength(replace);
     if (replaceLen == 0) return NULL;  // Empty replace causes infinite loop during count
 
     if (!by) by = "";           // Replace by nothing if not provided
-    byLen = strlen(by);
+    byLen = TextLength(by);
 
     // Count the number of replacements needed
     insertPoint = text;
     for (count = 0; (temp = strstr(insertPoint, replace)); count++) insertPoint = temp + replaceLen;
 
     // Allocate returning string and point temp to it
-    temp = result = RL_MALLOC(strlen(text) + (byLen - replaceLen)*count + 1);
+    temp = result = RL_MALLOC(TextLength(text) + (byLen - replaceLen)*count + 1);
 
     if (!result) return NULL;   // Memory could not be allocated
 
@@ -1254,12 +1252,12 @@ char *TextReplace(char *text, const char *replace, const char *by)
 }
 
 // Insert text in a specific position, moves all text forward
-// REQUIRES: strlen(), strcpy(), strtok()
+// REQUIRES: strcpy()
 // WARNING: Allocated memory should be manually freed
 char *TextInsert(const char *text, const char *insert, int position)
 {
-    int textLen = strlen(text);
-    int insertLen =  strlen(insert);
+    int textLen = TextLength(text);
+    int insertLen =  TextLength(insert);
 
     char *result = (char *)RL_MALLOC(textLen + insertLen + 1);
 
@@ -1280,11 +1278,11 @@ const char *TextJoin(const char **textList, int count, const char *delimiter)
     memset(text, 0, MAX_TEXT_BUFFER_LENGTH);
 
     int totalLength = 0;
-    int delimiterLen = strlen(delimiter);
+    int delimiterLen = TextLength(delimiter);
 
     for (int i = 0; i < count; i++)
     {
-        int textListLength = strlen(textList[i]);
+        int textListLength = TextLength(textList[i]);
 
         // Make sure joined text could fit inside MAX_TEXT_BUFFER_LENGTH
         if ((totalLength + textListLength) < MAX_TEXT_BUFFER_LENGTH)
@@ -1348,7 +1346,7 @@ const char **TextSplit(const char *text, char delimiter, int *count)
 void TextAppend(char *text, const char *append, int *position)
 {
     strcpy(text + *position, append);
-    *position += strlen(append);
+    *position += TextLength(append);
 }
 
 // Find first text occurrence within a string
@@ -1365,14 +1363,17 @@ int TextFindIndex(const char *text, const char *find)
 }
 
 // Get upper case version of provided string
-// REQUIRES: toupper()
 const char *TextToUpper(const char *text)
 {
     static char buffer[MAX_TEXT_BUFFER_LENGTH] = { 0 };
 
     for (int i = 0; i < MAX_TEXT_BUFFER_LENGTH; i++)
     {
-        if (text[i] != '\0') buffer[i] = (char)toupper(text[i]);
+        if (text[i] != '\0')
+        {
+            //buffer[i] = (char)toupper(text[i]);
+            if ((text[i] >= 'a') && (text[i] <= 'z')) buffer[i] = text[i] - 32;
+        }
         else { buffer[i] = '\0'; break; }
     }
 
@@ -1380,14 +1381,17 @@ const char *TextToUpper(const char *text)
 }
 
 // Get lower case version of provided string
-// REQUIRES: tolower()
 const char *TextToLower(const char *text)
 {
     static char buffer[MAX_TEXT_BUFFER_LENGTH] = { 0 };
 
     for (int i = 0; i < MAX_TEXT_BUFFER_LENGTH; i++)
     {
-        if (text[i] != '\0') buffer[i] = (char)tolower(text[i]);
+        if (text[i] != '\0')
+        {
+            //buffer[i] = (char)tolower(text[i]);
+            if ((text[i] >= 'A') && (text[i] <= 'Z')) buffer[i] = text[i] + 32;
+        }
         else { buffer[i] = '\0'; break; }
     }
 
@@ -1395,12 +1399,11 @@ const char *TextToLower(const char *text)
 }
 
 // Get Pascal case notation version of provided string
-// REQUIRES: toupper()
 const char *TextToPascal(const char *text)
 {
     static char buffer[MAX_TEXT_BUFFER_LENGTH] = { 0 };
 
-    buffer[0] = (char)toupper(text[0]);
+    buffer[0] = (char)TextToUpper(text[0]);
 
     for (int i = 1, j = 1; i < MAX_TEXT_BUFFER_LENGTH; i++, j++)
     {
@@ -1410,7 +1413,7 @@ const char *TextToPascal(const char *text)
             else
             {
                 j++;
-                buffer[i] = (char)toupper(text[j]);
+                buffer[i] = (char)TextToUpper(text[j]);
             }
         }
         else { buffer[i] = '\0'; break; }
@@ -1466,7 +1469,7 @@ int *GetCodepoints(const char *text, int *count)
     memset(codepoints, 0, MAX_TEXT_UNICODE_CHARS*sizeof(int));
 
     int bytesProcessed = 0;
-    int textLength = strlen(text);
+    int textLength = TextLength(text);
     int codepointsCount = 0;
 
     for (int i = 0; i < textLength; codepointsCount++)
@@ -1721,12 +1724,12 @@ static Font LoadBMFont(const char *fileName)
     }
 
     // NOTE: We need some extra space to avoid memory corruption on next allocations!
-    texPath = RL_MALLOC(strlen(fileName) - strlen(lastSlash) + strlen(texFileName) + 4);
+    texPath = RL_MALLOC(TextLength(fileName) - TextLength(lastSlash) + TextLength(texFileName) + 4);
 
     // NOTE: strcat() and strncat() required a '\0' terminated string to work!
     *texPath = '\0';
-    strncat(texPath, fileName, strlen(fileName) - strlen(lastSlash) + 1);
-    strncat(texPath, texFileName, strlen(texFileName));
+    strncat(texPath, fileName, TextLength(fileName) - TextLength(lastSlash) + 1);
+    strncat(texPath, texFileName, TextLength(texFileName));
 
     TRACELOGD("[%s] Font texture loading path: %s", fileName, texPath);
 

src/textures.c

@@ -65,8 +65,8 @@
 #endif
 
 #include <stdlib.h>             // Required for: malloc(), free()
-#include <string.h>             // Required for: strlen()
 #include <stdio.h>              // Required for: FILE, fopen(), fclose(), fread()
+#include <string.h>             // Required for: strlen() [Used in ImageTextEx()]
 
 #include "utils.h"              // Required for: fopen() Android mapping
 

src/utils.c

@@ -78,7 +78,6 @@ static UWPMessage *UWPInMessages[MAX_UWP_MESSAGES];     // Messages in from UWP
 // Module specific Functions Declaration
 //----------------------------------------------------------------------------------
 #if defined(PLATFORM_ANDROID)
-// This should be in <stdio.h>, but Travis does not find it...
 FILE *funopen(const void *cookie, int (*readfn)(void *, char *, int), int (*writefn)(void *, const char *, int),
               fpos_t (*seekfn)(void *, fpos_t, int), int (*closefn)(void *));